A study of structural development in the high speed spinning of poly(ethylene terephthalate)

In recent years the spinning speeds of poly(ethylene terephthalate) (PET) fiber have increased to the point that significant structural development is being observed in the spun yarn. At even higher speeds significant crystallization has been obtained. Data characterizing these yarns will be presented and discussed showing the development of crystals and that the onset of this phenomena is related to the stress at the “freeze point.” The “freeze point” rises from around Tg at low speeds to the order of 200°C at high speeds. The spinline itself has been characterized by velocity and orientation profiles which show the crystallization process is extremely rapid, occurring over a few centimenters of the spinline.